US3378666A

US3378666A - Switch enclosure with multiple interlocks

Info

Publication number: US3378666A
Application number: US635824A
Authority: US
Inventors: Tadeusz J Rys
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1967-05-03
Filing date: 1967-05-03
Publication date: 1968-04-16
Anticipated expiration: 1985-04-16

Description

April 16, 1968 T. J. RYS 3,378,666

SWITCH ENCLOSURE WITH MULTIPLE INTERLOCKS Filed May 5, 1967 7 Sheets-Sheet 1 1 .1. INVENTOR.

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April 16, 1968 'r. J. RYS

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SWITCH ENCLOSURE WITH MULTIPLE INTERLOCKS '7 Sheets-Sheet 5 Filed May 3, 196'? INVENTOR. y 2 B April 16, 1968 T. J. RYS

SWITCH ENCLOSURE WITH MULTIPLE INTERLOCKS '7 Sheets-Sheet 4 Filed May 3, 1967 INVgTOR. BYJM? 374/,

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SWITCH ENCLOSURE WITH MULTIPLE INTERLOCKS Filed May 5, 1967 7 Sheets-Sheet 5 l l L. .,.J

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April 16, 1968 Filed May 3, 1967 T. J. RYS

SWITCH ENCLOSURE WITH MULTIPLE INTERLOCKS 7 Sheets-Sheet 6 INVENTOR. all Q 0, ,BY

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SWITCH ENCLOSURE WITH MULTIPLE INTERLOCKS April 16, 1968 7 Sheets-Sheet 7 Filed May INVENTOR. @74

A 7'7'OENEY United States Patent 3,378,666 SWITCH ENCLOSURE WITH MULTIPLE INTERLOCKS Tadeusz J. Rys, Lexington, Ky., assignor to Square D Company, Park Ridge, 11]., a corporation of Michigan Filed May 3, 1967, Ser. No. 635,824 11 Claims. (Cl. 200-168) ABSTRACT OF THE DISCLOSURE The switch enclosure comprises a box 1 having a front door 3. A switch operating bar within the box is operated with a snap action by a cam 18 driven by a shaft 11 connected to an exterior handle 10. A gasket 4 is arranged for sealing between the door and box. A sealing mechanism, including a sliding interlock bar 39 within the box, cooperates with

fingers

32 and 34 on the door for drawing the door tightly into sealing position upon operation of the bar by a lug 38 extending into the box from an exteriorarily operated sealing lever 36 on the shaft 11. A rocker 45 is mounted in the box and is movable to interlocking position by a spring 48 wherein an end portion 49 blocks the movement of the bar out of sealing position until the rocker 45 is tripped. The rocker is movable to release position by an interlock release 50.

Interlock means within the box are operative when both the handle and lever 36 are in OFF position to prevent movement of the handle 10 to ON position and are operative to release the handle 10 for movement to ON and OFF positions when the lever 36 is moved to sealing position.

This invention relates to a switch enclosure in the form of a box having a service opening, a door for the opening, and a sealing gasket interposed between the door and box so that when the door is drawn tightly into final closed position a dust and weatherproof seal is provided between the door and box to prevent ingress of foreign matter, gases, moisture, and the like through the opening, and having a minimum of openings for cables and for connections between manually operable external elements with their associated mechanisms and devices within the box. More specifically the invention relates to a switch enclosure of this character including a switch operating mechanism within the box operable by a manually operable external operating handle to open switch and closed switch positions; a door sealing mechanism within the box operable by a manually operable external sealing lever; interlocks for the mechanisms; and defeaters which have portions exposed for access by a tool at the exterior of the box so that the interlocks can be defeated for servicing the switch and related structure within the box when so desired.

The interlocks are such that:

(a) The switch operating mechanism, when in open switch position, cannot be moved to closed switch position until the door not only is closed, but is drawn into tight sealing engagement with the gasket, after which the switch operating mechanism can be moved by its external operating handle to open and close a switch within the box;

(b) The closed sealed door can be released for opening when the switch operating mechanism is in open switch position by deliberate manipulation of one external defeater;

(c) The door can be released and opened with the switch operating mechanism in closed switch position by deliberate successive operations of the one defeater and a second defeater; I

(d) The switch operating mechanism can be moved to open switch position after the door has been opened, but cannot be returned to closed switch position until the 3,378,666 Patented Apr. 16, 1968 ice door has been not only closed, but also sealed, except by operation of a defeater; and

(e) The door, when sealed, is constrained to the seal ing position so long as the switch operating mechanism is in the closed switch position, unless released by the deliberate manipulation of the defcaters.

The present enclosure reduces to a minimum the possibility of accidental operation of the switch in a manner which could injure personnel operating and servicing a switch and accompanying equipment within the box, or the mechanisms, interlocks, and defeaters, and also reduces to a minimum the number of openings through which foreign matter such as airborne particles, moisture, corrosive gases, and other contaminants can enter.

Thus, as distinguished from prior enclosures, not only must the door be closed, but it must be in sealed relation to the box before a switch therein can be closed, and only by deliberate defeating of the interlocks with a screwdriver, can the operating handle be operated to close the switch while the cover i open or unsealed, and two interlocks must be defeated with a screwdriver, one to break the seal in order to fully release the door while the switch is closed.

These safety features are devised to meet conditions existing in the field. For example, it is known that most maintenance electricians, after having completed their servicing of the switch, will not take the time to tighten down the usual screws or bolts provided for drawing the door into sealed position on a switch box. As a result dust and airborne particles of foreign matter, moisture, and contaminating gases can enter the switch box. However, by making the structure so that the door must be sealed before the switch can be operated, this human error is overcome.

By arranging the operating mechanisms as hereinafter disclosed, the number of openings through which connections between exterior operable elements and their associated interior operated devices, is greatly reduced, thus further reducing the chances for infiltration of foreign matter and contaminants.

To this end, a specific feature of the invention is the arrangement of an external switch operating handle and an external door sealing lever for rotation about a common axis, thereby reducing the apertures required in the enclosure as compared to prior structures.

Another feature resides in the provision of an anti-coin cup connected with the defeaters so as to prevent their operation from the exterior of the enclosure by insertion of a coin into the operating element which is meant to be operated by a special tool, such as a screwdriver.

Various other objects and advantages will become apparent from the following description wherein reference is made to the drawings, in which:

FIG. 1 is a front elevation of the enclosure with a switch operating handle and operating parts in. ON position;

FIG. 2 is a right side elevation of the structure shown in FIG. 1;

FIG. 3 is a vertical sectional view taken on the line 3-3 in FIG. 1;

FIG. 4 is a fragmentary front elevation showing the door release screw in actuated position;

FIG. 5 is a sectional view similar to FIG. 3, parts thereof being shown in elevation for clearance, with the operating parts for the switch in the ON position and the door closed but unsealed;

FIG. 6 is a view similar to FIG. 5, but showing the operating parts for the switch in OFF position and the door closed and sealed;

FIG. 7 is a fragmentary view similar to FIG. 3, but showing the door in the unsealed and open position in which the switch cannot be closed;

FIG. 8 is a fragmentary sectional view through the operating handles and associated parts, and is taken on the line 8-8 of FIG. 6; and

FIG. 9 is an exploded view of a fragment of the enclosure showing the exterior operating handle, sealing lever, and associated parts.

Referring to the drawings, the switch enclosure comprises a sheet metal box 1 having side and rear walls, a forward open face with a peripheral edge 2, and a door 3 which is connected to a side wall of the box, for swinging freely into and out of closed position, by hinges spot welded -to the door and to a side wall of the box.

As hereinbefore mentioned, it is desirable not only that the door be closed and held in closed position, but that an effective seal be provided between the peripheral margin of the door and the aligned peripheral edge 2 of the box. For this purpose, a resilient gasket 4 is mounted on the margin of the inner face of the door in a position to be engaged and drawn tightly against the edge 2 of the box when the door is in closed sealed position.

Mounted within the box is the usual operating bar 5 which carries a plurality of movable contacts 6 for cooperation with a plurality of stationary contacts 7 mounted on the rear wall of the box. One end of the bar is rockably supported at one end by a bracket 8, welded to one side wall. In order to operate the switch, an extraneous switch operating handle 10, comprising two laterally spaced and aligned metal arms 10a, is mounted on a suitable rock shaft 11. The shaft 11 extends through a suitable handle bearing 12, having a rotation limiting boss 12a, and through an external boss 13 which is integral with the side wall of the box. The boss 12a is integral with the bearing 12 and is of constant radius and coaxial with the shaft 11 and extends partway circumferentially of the shaft in radially outwardly spaced relation thereto. The handle bearing 12 is secured in non-rotative relation with respect to the boss 13 by means of bolts 14 which extend through holes in the bearing 12 at the ends of the boss 12a.

The shaft 11 supports the handle portions 10a for rocking as a unit with the shaft relative to the bearing about the shaft axis, preferably by providing suitable hexagonal or out-of-round openings in the handle portions fitting with a like hexagonal or out-of-round shank portion of the outer end of the shaft 11. On the out-of-round portion of the shaft inside of the box and adjacent the boss 13, a cam operator 15 is mounted for rotation or rocking with the shaft 11. This connection is effected by means of a hexagonal opening 16 in the operator 15 fitting the hexagonal cross-section of the shaft 11. The cam operator carries at its outer margin a lug 17 which is arranged to engage and operate a cam 18 drivingly connected to the switch operating bar 5.

Since the cam 18 must be operated with lost motion relative to the handle 10, a lost motion connection is provided between the cam operator 15 and the cam 18. The cam comprises a plate mounted on the inner end portion 19 of the shaft 11 for free rotation relative to the shaft 11. The plate has a pair of circumferentially spaced lugs 20 disposed on opposite sides of the adjacent bent-over end portion 21 of the operating bar 5. The free end of the portion 21 is rotatably mounted in a bracket in coaxial relation to the opposite free end of the bar 5.

A lug 17 on the cam operator 15 is operable in a slot 22 in the cam 18 and is of less extent circumferentially of the axis of the shaft 19 than the slot 22. A suitable link 23 is pivotally connected at one end to the box and at the other end carries a pin 24 operable with a lost motion in a circumferential slot 25 in the cam 18. A dead center spring 26 is carried on the link 23 and is operative to drive the cam 18 to the open switch position when the cam 18 is moved by the handle 10 and operator 15 past dead center in the switch opening direction, and to closed switch position when the cam 18 is moved by the handle 10 and Gil 4 cam operator 15 past dead center in the switch closing direction.

A lost motion connection between the cam operator and the cam is provided by suitable fingers 27 on the cam operator and aligned fingers 28 on the cam. A coil compression spring 29 embraces one finger of the cam 18 and one finger of the operator 15 at one end of the spring and the other finger of the cam and other finger of the operator at the opposite end of the spring. Thus by rocking the handle 1t clockwise in FIG. 2, the cam operator drives the cam 18 past dead center in the switch closing direction and thereby the switch bar 5 is moved to swing the movable contacts of the switch to closed position with a snap action. Upon rocking the handle 10 in the opposite direction, the cam is operated to cause the switch bar 5 to move with a snap action to the open position.

As mentioned, it is desirable that the door be drawn tightly into sealed position when closed. For this purpose, the door is provided with an upper interlock plate 30 and a lower interlock plate 31. The upper plate 30 is rigidly secured to the inside of the door and has an upper wedge or sealing finger 32 and a lower interlock finger 33. The lower plate 31 has a wedge or sealing finger 34.

In order to seal the door in closed position with the switch operation in open switch position and, while so held, a sealing mechanism cooperating with the

fingers

32 and 34 is operated. This sealing mechanism comprises an external sealing lever 36 which is mounted about the shaft 11 for rocking relative thereto about the axis thereof. The lever carries at its inner end a radially enlarged portion 37 having an internally extending finger or lug 38. The lug 38 is in driving engagement with a cover interlock bar 39. The interlock bar 39 extends along the inner face of "the side wall of the box, generally parallel to the plane of the door, adjacent the handle 36 and near the margin of the open face of the box. The bar 39 is secured in place for movement endwise of the door along the adjacent side wall of the box by means of suitable pins 40 disposed in elongated slots 41 in the bar. Thus, upon rocking of the lever 36 clockwise, the cover interlock bar 39 is moved toward the upper end of the box. The bar 39 is provided at its upper end with a wedge finger 42 and at its lower end with a wedge finger 43. When the bar is moved toward the upper end of the box by rocking the lever 36 clockwise in .FIG. 2, the wedge finger 42 engages in camming relation with wedge finger 32 on the door, and the wedge finger 43 engages in camming relation with the wedge finger 34 on the door. The

fingers

32 and 34 are sloped relative to the face of the door so that when so engaged by

fingers

42 and 43 as the door interlock bar 39 is moved upwardly, they draw the door firmly toward the exposed forward edges of the side walls of the box and thus compress the gasket 4 sufliciently tightly against such edges for sealing the box. A compression spring 44 restores the bar 39 to door releasing position When the bar itself is released.

As mentioned, however, it is desirable that the door be not only closed, but also in sealed relation before the switch operator can be moved from open switch to closed switch position by the operating handle 10. For this purpose, interlocks of the switch operating mechanism, cover sealing mechanism, and the door are provided, as will now be described.

One of the interlocks for the sealing mechanism is mounted on the door and arranged for movement into engagement with the lower end of the interlock bar 39 when the interlock bar is held in the door sealing position by the lever 36. This interlock comprises a rocker 45 which is pivotally connected by a pivot 46 to a suitable supporting plate or bracket 31 which in turn is fixedly spot welded to the door in face to face relation to the inner face thereof. The rocker 45 is urged to the interlocking position by means of a compression spring 48. In this position, the upper bent-over end 49 of the rocker engages the lower end of the bar 39 and prevents movement of the bar downwardly out of door sealing position until the rocker 45 release the bar 39. In order to trip the rocker 45 and move it out of interlocking position with respect to the bar 39, an interlock release is provided. The interlock release 56 com- .prises a rocker arm 51 disposed between the door and to the rocker 45 and having an upturned end 52 which engages an elongated slot 53 in the rocker 45. The arm 51 is mounted on a rotatable shaft 54 for rotation therewith. The shaft is rotatably mounted in the door and the outer end of the shaft is provided with an enlarged head 55 exteriorly of the door. The head 55 has slot 56 for receiving the tip of a screwdriver for rotating the shaft 54 and thereby rocking the arm 51 to rock the rocker 45 about its pivot 46 against the force of the spring 48 to remove the upper bent-over end 49 from beneath the lower end of the bar 39. When the lower end of the bar 39 is released, the spring drives it downwardly to a position wherein the

fingers

42 and 43 release the

wcdge fingers

32 and 34, respectively. This movement also moves the lever 36 to its starting unsealing position.

A suitable anti-coin cup 57 is carried on the shaft between the head 55 and the door, and is disposed so as to prevent the insertion of a coin into the slot 56 for defeating the interlock of the rocker 45 and bar 39.

In order to prevent closure of the switch while the door is open or before it is sealed, a door interlock 60 is provided. The door interlock 69 comprises a rocker 61 which has a finger 61a, FIG. 1, and which is mounted on a shaft 62 extending parallel to the shaft 11. The rocker is secured to the shaft 62 for rotation therewith. At its outer end the shaft 62 carries a slotted head 63 for rocking the shaft, and thereby the rocker 61, to release position from the exterior of the box, thereby providing an interlock release or defeater. Referring to FIG. 7, the rocker 61 is normally urged in a clockwise direction by a spring 64. The rocker has a surface 65 which, in the open switch position of the switch operating cam 18 with the door unsealed underlies a finger 66 of the cam 18, and thus prevents moving the handle 10 counter-clockwise to the closed switch position. Upon operating the lever 36 to seal the door, the rocker 61 is rocked by the bar 39 against the spring 64 to a position in which it removes the surface 65 from the path of the finger 66, thus permitting the cam 18 to be operated to close the switch. However, if it is desired to open the door while the switch is closed, the rocker 45 is operated by the interlock release 50 to release the bar 39,

whereupon the spring 41 causes the bar 39 to withdraw from the rocker 61 allowing the rocker under the influence of the spring 64 to swing toward the cam 18. Thereupon the edge 67 of the rocker, if the switch is ON, engages the periphery of the cam operator 15, thus holding the interlock in a position in which it cannot interfere with the opening of the switch by the handle 10. However, in this position of the rocker 61, the finger 61a is positioned to overlie the finger 33 of the door, FIGS. 6 and 7, and thus prevent opening of the door while the switch is ON, even though the door is unsealed. As the handle 10 is moved farther in the opening direction, the periphery of the cam operator passes out of engagement with the edge 67 of the rocker 61, but just before this happens, the one of the fingers 2d of the cam 18, which is to open the switch, engages the edge 67 and holds the rocker in the same position until the cam snaps to open switch posittion and releases the rocker 61 so that it rocks to interlock position with the cam finger 66 and prevents reclosure of the switch. A stop rod 68 is mounted in the box in position to limit the movement of the cam 18 by its spring 26 in the opening direction after the cam has opened the switch.

If it is desired to open the door with the switch ON, then the shaft 62 is operated by inserting a screwdriver 6 in the slot of its head 63 and rotating the shaft 62 thereby positioning the rocker 61 so that all of its surfaces are in inoperative position with respect to the cam 18, earn operator 15, and door finger 33. Thus the door can be opened with the switch ON.

Once the lever 36 has been moved to effect the seal, the door cannot be opened whether the switch is opened or closed without operating the rocker 415 to defeat the sealing operation of the bar 39. If the switch is closed, then the rocker 45 and the rocker 61 must both be released.

If it is desired to close the switch with the door open, this can be done by operating the interlock 60 to release the cam operator 15. It can also be done by swinging the lever 36 in the sealing direction when the door is fully open and, while holding the lever 36 in the sealing position, closing the switch by the handle 10.

It is readily seen that the switch is safe from accidental operation. The handle bearing plate 12 is provided with a circumferentialiy extending slot 70 positioned so that when the switch is in OFF position, a number of padlock hasps may be passed through the slot to prevent accidental closure of the switch by the handle 10. Thus, in the present structure, normally the door must be closed and sealed before the switch can be turned ON, and to do this it is only necessary, while the switch is OFF, to close the door and to swing the sealing lever 36 to scaling position. This completely closes and also seals the switch box. While this condition exists the switch can be turned OFF and ON as desired.

The switch operating mechanisms, the door latching and sealing means, and the interlocks, are all located inside the box. The sealing mechanism earns the door down tightly against the open face of the box at two widely spaced points to assure an effective sealing face.

If it is desired to open the door with the handle 10 in ON position, a screwdriver must be inserted in the notch 56 and turned to release the rocker 45 from the bar 39. The screwdriver must then be inserted in the slotted head 63 of the shaft 62 for releasing the interlock rocker 61. With the screwdriver in the latter position the door can be opened.

If a number of the switch boxes are close ganged so that access to the notch in the head 63 with a screwdriver directed axially of the shaft 62 is precluded, then the point of the screwdriver may be inserted along the side wall rearwardly of the 'box behind the interlock lever 36 between the wall and the switch handle 10 and thence into the slot of the interlock, the screwdriver being swung circumferentially of the axis of the shaft 62 for releasing the interlock.

The switch can be turned OFF after the door has been opened, but it cannot be turned ON again before the door has not only been closed, but also sealed, unless the interlocks are deliberately defeated. If the door has been opened with the switch ON, the door may be closed, but not sealed, unless the sealing lever 36 is fully depressed. This occurs only when the door has been opened, with the switch ON, for inspection. The location of the sealing lever 36 will quickly reveal this condition. Again, the switch can be turned OFF only once before the door has to be both closed and sealed again to permit normal operation.

It is apparent that with the present switch box, the openings into the box are reduced to a minimum and these openings are small and readily sealed. One is about the axis of the shaft 54, one about the axis of the shaft 62, and one about the common axis of the switch opening handle 10 and sealing lever 36.

The usual knock-out plugs are provided for the introduction of the necessary cables, but sealing can readily be effected between such cables and the edges of the holes resulting from removal of the plugs.

Having thus described my invention, I claim:

1. A switch enclosure comprising a box member having enclosing walls and having a service opening at the front,

a door member hingedly connected to the box member for movement to open and closed positions relative to the opening,

switch operating mechanism mounted in the box member for movement in opposite directions to ON and OFF positions, respectively,

an operating handle disposed exteriorly of the box member and drivingly connected to the switch operating mechanism for moving the mechanism to said positions, selectively,

a sealing gasket for the opening,

a sealing mechanism mounted in the box member for movement to sealing and releasing positions,

latch means on the inside of the door member engageable and operable, when the door member is closed, by the sealing mechanism to draw the members into firm sealing engagement with opposite faces of the gasket when the sealing mechanism is moved to sealing position, said latch means being released by the sealing mechanism when the sealing mechanism is moved to releasing position,

a sealing lever disposed exteriorly of the box member and drivingly connected to the sealing mechanism for moving the sealing mechanism to sealing position,

interlock means within the box member operative, when the handle is in OFF position and the lever in released poistion, to prevent movement of the handle to ON position, and rendered operative to release the handle for movement to ON and OFF positions upon movement of the lever to sealing position.

2. The structure according to claim 1 wherein said releasing means for the interlock means are mounted in the box member and include a tool operable element having a portion disposed for access by a tool exteriorly of the box member and operable by said tool to release said interlock means from the sealing mechanism, and

means to return the sealing mechanism and lever to unsealing and releasing position with respect to the door member when the sealing mechanism is released.

3. The structure according to claim 1 wherein switch interlock means for the switch operating mechanism are mounted in the box member and, when the door is closed but unsealed and the switch operating mechanism is in OFF position, are cooperative with the swltch operating mechanism to constrain the switch operating mechanism to OFF position, and are rendered inoperative with respect to the switch operating mechanism by the sealing mechanism when the lever is moved to sealing position, and thereby release the switch operating mechanism for operation by the handle to ON and OFF posttions.

4. The structure according to claim 3 wherein the switch interlock means include latch means,

the door member is provided with complementary latch means,

means are carried by the sealing mechanism and engage the switch interlock means and move the switch interlock means to cause the latch means of the switch interlock means and door member to disengage when the lever is moved to scaling positlon and to remain disengaged while the door member is held sealed by the sealing means, and to release the switch interlock means for return of the latch means to latching position when the sealing mechanism is released,

means in the box member for moving the switch interlock means to return the latch means to latching position with respect to the door member when the switch interlock means are released while the switch operating mechanism is in ON position.

5. The structure according to claim 4 wherein the switch operating mechanism includes means to release the switch interlock means when the switch operating mechanism is moved to OFF position.

6. The structure according to claim 4 wherein an auxiliary release for the switch interlock means is mounted in the box member and has a tool operated portion accessible by a tool at the exterior of the box member, and is operable by the tool to move the switch interlock means to position to render said latch means of the door member and switch interlock means inoperative, so that the door member can be opened with the switch operating mechanism in ON position.

7. The structure according to claim 1 wherein a shaft extends through one wall of one of the members, the operating handle is mounted on the shaft for rocking therewith, the shaft has a portion which etxends into the box member and which is drivingly connected to the switch operating mechanism, and

the lever is supported for rotation concentrically with respect to said shaft.

8. The structure according to claim 7 wherein said one wall has an opening, a lug is provided on the lever and extends therethrough and is drivingly connected to the sealing mechanism.

9. A switch enclosure comprising a box member having enclosing walls, including a side wall, and having a service opening at the front,

switch operating mechanism mounted on and in the box member for movement in opposite direction to ON and OFF positions, respectively, a

an operating handle disposed exteriorly of the box member, pivoted on the side wall, and drivingly connected to the switch operating mechanism for moving the mechanism to said positions, selectively,

latch means on the inside of the door member engageable and operable, when the door member is closed, by the sealing mechanism to draw the members into firm sealing engagement when the sealing mechanism is moved to sealing position, said latch means being released by the sealing mechanism when the sealing mechanism is moved to releasing position,

a sealing lever disposed etxeriorly of the box member along the side wall and drivingly connected to the sealing mechanism for moving the sealing mechanism to sealing position,

interlock means within the box member operative, when the handle is in OFF position and the lever in released position, to prevent movement of the handle to ON position, and rendered operative to release the handle for movement to ON and OFF positions upon movement of the lever to sealing position.

10. The structure according to claim 9 wherein the operating handle is pivoted coaxially with the pivot of the sealing lever.

11. The structure according to claim 9 wherein the sealing lever is mounted on the box for rotation coaxially with respect to the pivot point of the operating handle.